1. Field of the Invention
The present invention relates to cosmetic and/or dermatological compositions which contain a superoxide dismutase (SOD) together with a porphyrin.
2. Discussion of the Background
Such compositions, which are used topically, make it possible to combat skin ageing and/or to protect the skin against the effects of free radicals which are induced, for example, by atmospheric pollutants and/or by ultraviolet radiation. It fact known that the toxicity of atmospheric pollutants, especially gaseous pollutants such as sulphur dioxide, ozone and oxides of nitrogen, is linked to their activity as initiators of free radicals, which are the source of oxidation phenomena which cause damage to the cells of living beings. The cells of organs which are in direct and permanent contact with the external environment, such as the skin, scalp and some mucosae, are particularly sensitive to these effects of the gaseous pollutants, which are manifested in particular in accelerated ageing of the skin, with a dull complexion and the premature formation of wrinkles and lines, and also in a reduction in the vigor and a dull appearance of the hair.
It is known that superoxide dismutases are enzymes which are capable of inducing the dismutation of superoxide ions in accordance with the reaction: EQU 2O.sup.-.sub.2 +2H.sup.+ .fwdarw.H.sub.2 O.sub.2 +O.sub.2
Numerous superoxide dismutases are known. For example, a superoxide dismutases extracted from bovine erythrocytes (Markovitz, J. Biol. Chem. 234, p. 40, 1959) and superoxide dismutases extracted from Escherichia coli (Keele and Fridovich, J. Biol. Chem., 245, p. 6176, 1970) are known. U.S. Pat. No. 3,920,521 describes superoxide dismutases extracted from marine bacterial strains, and also processes for their preparation.
Superoxide dismutases make it possible to protect the skin and hair, especially while maintaining the integrity of the natural keratinous structure, as described for example by U.S. Pat. No. 4,129,644. In addition, superoxide dismutases improve the skin cell respiration and maintain or enhance the qualities of the skin such as softness to the touch, suppleness and elasticity. Their presence in compositions for hair also enables the condition of the scalp to be maintained or enhanced while also protecting the skin on the hands of the person applying these compositions.
The superoxide dismutases additionally protect the skin against the inflammatory phenomena caused by ultraviolet radiation and against the accelerated ageing of the skin, especially under the influence of such radiation.
By virtue of these various properties, superoxide dismutases can be used in cosmetic compositions for the skin, hair and/or mucosae and in pharmaceutical compositions for dermatological use.
Superoxide dismutases act against oxygen-containing free radicals. The superoxide ion O.sup.-.sub.2 (active oxygen) is a radical ion whose instability and reactivity make it toxic because it gives rise to highly damaging hydroxyl free radicals (.OH), especially in the presence of metal ions. Superoxide dismutases exert a protective effect, in particular, by trapping the superoxide ions, and therefore constitute a biological defense system against the harmful effects of the oxygen-containing free radicals.
Unfortunately, superoxide dismutases used alone in a cosmetic composition have a degree of effectiveness which is insufficient to trap completely the oxygen-containing free radicals. In order to solve this problem, it has already been envisaged to combine it with a sequestering agent of the phosphonic type (see U.S. Pat. No. 5,352,438).
The use of hemin and hematin to protect the skin from sunlight and to prevent the ageing of the skin is known (JP-A-02019311). FR-A-2,693,904 discloses the use of chlorophylis for restructuring the skin and, in addition, for preventing the ageing of the skin. However, these documents in no way describe nor suggest to use a porphyrin with a superoxide dismutase with the intention of reinforcing, with synergy, the activity of the latter.